A microprocessor controlled induction motor by an adaptive indirect field orientation

A 1.2 kW four-quadrant AC-drive is developed, in which the control is implemented with a microcomputer and the motor is supplied by a voltage-source inverter with current control using IGBTs. A self-adaptive scheme is described for automatically tracking the temperature and saturation dependent rotor time constant. The main advantage of this adaptive scheme is to merge two simple techniques without the use of additional sensors, while adding only a little more software overhead